My PhD project WINTERGAP aims at improving physical winter process representation in the LPJ-GUESS dynamic vegetation model. The development phase consists of three sub-projects that will enhance the performance of LPJ-GUESS in simulating arctic conditions:

1. Snow insulation: an intermediate complexity, multi-layer snow scheme will be included to enable analysing snow-vegetation-soil interactions, affecting permafrost conditions.
2. Vegetation damage due to extreme events: cold hardiness, frost damage and winter drought are to be included, making it possible to simulate the observed tissue damage in the region, due to extreme weather conditions in the cold season.
3. Cold season fluxes: a dynamic soil gas reservoir for CO₂ and CH₄ will be defined to introduce the capability to simulate shoulder period and cold season carbon fluxes.

By implementing the proposed developments we will be able to assess how the warming winter season may affect arctic ecosystems, evaluate regional permafrost-climate feedbacks and discuss the role of the Arctic in the global carbon cycle.